Mosca, CO frost dates
Last spring frostMay 30median date
First fall frostSep 17median date
Growing season110 daysfrost-free
Hardiness zone5aZone 5a
How Mosca compares
- In 8 years out of 10, the last spring frost in Mosca falls between May 17 and June 13, a 27-day window. The first fall frost falls between September 4 and September 27.
- The median last frost is 19 days later than the Colorado median of May 11.
- Its 110-day growing season is longer than 17% of the 374 Colorado places with a regular frost season (state median 146 days).
- The last frost is 27 days later than the zone 5a median of May 3. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 5a chart.
- The weather station records an average of 221 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 17 |
| 50% (median) | May 30 |
| 10% (safe for tender plants) | June 13 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 4 |
| 50% (median) | September 17 |
| 90% (late) | September 27 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Mosca, CO
Mosca, CO frost dates — last frost May 30, first frost Sep 17, zone 5a. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Mar 7 to Mar 21Transplant outside: May 2 to May 16
Start indoors: Mar 21 to Apr 4Transplant outside: Jun 13 to Jun 27
Start indoors: Mar 21 to Apr 4Transplant outside: Jun 13 to Jun 27
Start indoors: Apr 4 to Apr 18Transplant outside: Jun 6 to Jun 20
Start indoors: Apr 4 to Apr 18Transplant outside: May 9 to May 23Sow outdoors: May 2 to Jun 6Plant for fall: Jul 23 to Aug 20
Start indoors: Apr 4 to Apr 18Transplant outside: May 2 to May 16Sow outdoors: May 2 to May 16Plant for fall: Jul 9 to Jul 30
Start indoors: Apr 4 to Apr 18Transplant outside: May 16 to May 30
Start indoors: Apr 4 to Apr 18Transplant outside: May 9 to May 23
Start indoors: Apr 4 to Apr 18Transplant outside: May 16 to May 30
Start indoors: Apr 18 to May 2Transplant outside: Jun 20 to Jul 4Sow outdoors: Jun 20 to Jul 4
Start indoors: Apr 18 to May 2Transplant outside: Jun 6 to Jun 20
Sow outdoors: Apr 18 to May 9Plant for fall: Jun 25 to Jul 16
Sow outdoors: Apr 18 to May 9Plant for fall: Jul 23 to Aug 13
Sow outdoors: Apr 25 to Jun 6Plant for fall: Aug 6 to Aug 27
Start indoors: May 2 to May 9Transplant outside: Jun 13 to Jun 20Sow outdoors: Jun 6 to Jun 20
Start indoors: May 2 to May 9Sow outdoors: Jun 6 to Jun 20Plant for fall: Jul 9 to Jul 23
Start indoors: May 2 to May 9Sow outdoors: Jun 6 to Jun 20
Start indoors: May 2 to May 9Transplant outside: Jun 13 to Jun 27
Sow outdoors: May 9 to Jun 6Plant for fall: Jun 25 to Jul 9
Sow outdoors: May 9 to Jun 6Plant for fall: Jul 9 to Jul 23
Sow outdoors: May 9 to May 30
Sow outdoors: May 16 to Jun 13Plant for fall: Jul 9 to Jul 23
Sow outdoors: May 16 to Jun 6Plant for fall: Jul 23 to Aug 13
Sow outdoors: Jun 6 to Jun 27
Sow outdoors: Jun 6 to Jun 20
Transplant outside: Jun 13 to Jul 4
Plant for fall: Sep 3 to Oct 8
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Mosca, CO
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Mar 7 – Mar 21 | May 2 – May 16 | — | — |
| Peppers | Mar 21 – Apr 4 | Jun 13 – Jun 27 | — | — |
| Eggplant | Mar 21 – Apr 4 | Jun 13 – Jun 27 | — | — |
| Tomatoes | Apr 4 – Apr 18 | Jun 6 – Jun 20 | — | — |
| Lettuce | Apr 4 – Apr 18 | May 9 – May 23 | May 2 – Jun 6 | Jul 23 – Aug 20 |
| Kale | Apr 4 – Apr 18 | May 2 – May 16 | May 2 – May 16 | Jul 9 – Jul 30 |
| Broccoli | Apr 4 – Apr 18 | May 16 – May 30 | — | — |
| Cabbage | Apr 4 – Apr 18 | May 9 – May 23 | — | — |
| Cauliflower | Apr 4 – Apr 18 | May 16 – May 30 | — | — |
| Okra | Apr 18 – May 2 | Jun 20 – Jul 4 | Jun 20 – Jul 4 | — |
| Basil | Apr 18 – May 2 | Jun 6 – Jun 20 | — | — |
| Peas | — | — | Apr 18 – May 9 | Jun 25 – Jul 16 |
| Spinach | — | — | Apr 18 – May 9 | Jul 23 – Aug 13 |
| Radishes | — | — | Apr 25 – Jun 6 | Aug 6 – Aug 27 |
| Cucumbers | May 2 – May 9 | Jun 13 – Jun 20 | Jun 6 – Jun 20 | — |
| Zucchini & Summer Squash | May 2 – May 9 | — | Jun 6 – Jun 20 | Jul 9 – Jul 23 |
| Winter Squash & Pumpkins Warning: Your frost-free season is about 110 days, which is tight for winter squash & pumpkins (100+ days). Choose early varieties and use transplants or row covers. | May 2 – May 9 | — | Jun 6 – Jun 20 | — |
| Melons & Watermelon | May 2 – May 9 | Jun 13 – Jun 27 | — | — |
| Carrots | — | — | May 9 – Jun 6 | Jun 25 – Jul 9 |
| Beets | — | — | May 9 – Jun 6 | Jul 9 – Jul 23 |
| Potatoes | — | — | May 9 – May 30 | — |
| Swiss Chard | — | — | May 16 – Jun 13 | Jul 9 – Jul 23 |
| Cilantro | — | — | May 16 – Jun 6 | Jul 23 – Aug 13 |
| Green Beans | — | — | Jun 6 – Jun 27 | — |
| Sweet Corn | — | — | Jun 6 – Jun 20 | — |
| Sweet Potatoes Warning: Your frost-free season is about 110 days, which is tight for sweet potatoes (100+ days). Choose early varieties and use transplants or row covers. | — | Jun 13 – Jul 4 | — | — |
| Garlic | — | — | — | Sep 3 – Oct 8 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Alamosa 1e, CO weather station, 19 km away (elevation 7,539 ft (2,298 m)).
Frost dates near Mosca
- Hooper May 24 · Sep 24
- Alamosa May 30 · Sep 17
- Homelake Jun 11 · Sep 13
- Center May 24 · Sep 24
- Monte Vista Jun 11 · Sep 13
- Blanca May 25 · Sep 22
- Crestone May 26 · Sep 26
- La Jara May 28 · Sep 21
- Fort Garland May 25 · Sep 22
- Sanford May 28 · Sep 21
Frequently asked questions
When is the last frost in Mosca, CO?
The median last spring frost in Mosca, CO is May 30. There is still about a 10% chance of frost after June 13, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Mosca, CO?
The median first fall frost is September 17, with about a 10% chance of frost before September 4.
How long is the growing season in Mosca, CO?
About 110 days between the median last spring frost and first fall frost.
What planting zone is Mosca, CO?
Mosca, CO is in USDA hardiness zone 5a.